Yemeni officials and medics say a fierce battle between government troops and al-Qaida fighters in the country's south has killed at least 35 soldiers and 20 militants.

They say Sunday's fighting erupted in Abyan province, when the militants detonated several car bombs and overran a military post in the Koud region near the provincial capital, Zinjibar. Scores were wounded on both sides and the death toll is likely to rise.

Military officials said the insurgents were able to seize armored vehicles, artillery pieces, assault rifles and rockets from the army base they attacked. Some of the heavy weapons were later used against the troops, causing most of the casualties.

Al-Qaida militants seized control of Zinjibar last May while the government was pre-occupied with cracking down on nationwide opposition protests against the autocratic rule of then-President Ali Abdullah Saleh. Yemeni government forces have been trying to reclaim the town ever since.

Yemen has seen a surge in attacks blamed on al-Qaida since Saleh's deputy, Abed Rabo Mansour Hadi, took office as president last month under terms of a Gulf-backed deal to resolve the political crisis. Hours after Mr. Hadi's February 25 inauguration, a suicide bombing killed 26 soldiers at a presidential palace in the the eastern province of Hadramawt.

Mr. Hadi has said that fighting al-Qaida and restoring security in the impoverished Arab nation are among his top priorities.

Sunday's fighting followed the dismissal last week by Mr. Hadi's government of the military commander of the southern region, to which Abyan belongs, along with other security officials from the province.